INTRODUCTION: Adaptability to all types of terrain changes, slopes and course settings is a key aspect related to motor control that the best alpine skiers possess. In recent years, several studies have analyzed coordinative aspects of different motor actions by assessing movement variability (MV) through non-linear measurements. From the perspective of human movement, variability is described as the variation that occurs when executing multiple repetitions of the same task. Some of these studies already used an inertial measurement unit (IMU) placed at the athlete to assess MV. So far, no study has measured MV in alpine skiing nor its relationship to performance. Thus, the aims of this study were: a) to evaluate the influence of different slalom course settings on MV and b) to assess the relationship between MV and performance of elite alpine skiers. METHODS: Five elite alpine skiers completed several runs at maximum speed for four 10-gate slalom courses: a flat-turned (FT), a steep-turned (ST), a flat-straighter (FS) and a steep-straighter (SS). The SL courses were chosen to cover 4 different scenarios in terms of slope (flatter: 12° and steeper: 21°) and type of trajectory (turned course: 10.7/4 m and straighter course: 10.7/3.25 m for vertical gate distance and gate offset, respectively). The use of an IMU accelerometer attached to the lower back of skiers allowed the detection of MV through entropy. The skiers` performance was evaluated with the total time of each run. RESULTS: The linear mixed model used for the analysis revealed that the steepness of the slope has significantly increased skiers` MV. Specifically between FS and ST courses (p = 0.0082). Differences were found at a 10% level between FS and SS and FT and ST courses (p = 0.084 and p = 0.098, respectively). For a given slope, turned courses (FT and ST) tended to produce a higher MV. Pearson`s linear correlation coefficient revealed that there is a significant positive moderate linear correlation between MV and total time (r = 0.59, p = 0.010). DISCUSSION/CONCLUSION: Determining MV through entropy can be used as a way to assess adaptation to a type of stimulus. In this context, it has been observed that the best-performing skiers have lower MV and that steeper and turned courses produce greater MV in elite alpine skiers.
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